Pulling up Evil Thistle (and other bad weeds)

Today was a nice day. So, we went outside and went on a thistle hunt! We saw a lot of evil thistle and twisty vine-like weedy things. We know that weeds are bad because they take in minerals from the dirt. Plants that are planted near them do not get all the nutrients and can die! Some weeds can choke the plants by wrapping itself around the stems of a plant. The weed's leaves cover the plant's leaves and block out the sunlight and the plant can die. That's what the twisty vine-like weedy things were doing. Some weeds grew and spread out in a circle on the ground. Then they put down more roots and kept on growing. This blocks the sunlight from the ground and can stop plants from growing up. One of us found a thistle root with 2 thistles growing out of it! Amazing and terrible at the same time. 2 thistles for one root! AAARRRGGGHHH! The good news is that the cold weather is starting to kill the thistles, too! Some of the thistles we saw (and pulled out) were turning yellow.
Next week we're going on a field trip to tour a greenhouse!